Технологии применения химреагентов для снижения солеотложений при добыче нефти в ОАО «Варьеганнефтегаз»

Abstract

Background The main way of oil production (over 90 %) on the fields of Varyyeganneftegaz OAO is the mechanized by means of electric submersible pumps (ESP), predominantly (over 80 %) of domestic manufacture. Analysis of the ESP failures at Varyyeganneftegaz OAO revealed that over the past three years the largest number of failures is associated with the removal of mechanical impurities – 35 %, salt deposits – 16 % and corrosion – 7 %. Aims and Objectives The aim is to provide the analysis of the dependence of well operation complexity on the geological and physical characteristics of the productive strata and formation fluids and to develop the technology of chemical treatment in order to prevent them. Methods Analysis of scientific and technical literature, field data of pumping systems failure and reducing overhaul period, statistical analysis of geological and physical data and the results of chemical treatment aimed in reduce of scaling during the oil production at Varyyeganneftegaz OAO. Results There are determined the differences in geological and physical characteristics of the productive strata and formation fluids, leading to incompatibility of injection water used for reservoir pressure maintenance, as well as the changes in temperature and pressure conditions during field development leading to scaling during the oil development. The intensity of carbonate salts scaling increases while reducing the bottomhole pressure below the formation pressure in order to maintain a high recovery rate, or by application of calcium brines for killing wells. Conclusion Application of four technologies inhibiting scaling (constant reagent dosing by stationary installations SUDR, periodic – mobile MBRH block settings, use of encapsulated reagents and reagent filtered out into the reservoir) have reduced the specific number of failures per 100 wells per year to 1,5 times from 5,3 to 3,5. In 2001 there were processed 472 wells number of failure reduced to 25, in 2012 – respectively 576 wells were treated with 20 failures.